import sys
def main():
  input = sys.stdin.readline
  n, k = map(int , input().split())
  p_list = list(map(int, input().split()))
  c_list = list(map(int, input().split()))
  res = -float('inf')
  
  for s in range(n):
    S = []
    i = p_list[s] - 1
    S.append(c_list[i])
    while i != s:
      i = p_list[i]-1
      S.append(S[-1] + c_list[i])
    if k <= len(S):
      score = max(S[:k])
    elif S[-1] <= 0:
      score = max(S)
    else:
      score1 = S[-1] * (k//len(S) - 1)
      score1 += max(S)
      
      score2 = S[-1] * (k//len(S))
      r = k%len(S)
      if r!=0:
        score2 += max(0, max(S[:r]))
      score = max(score1, score2)
    res = max(res, score)
  print(res)
      

if (__name__=='__main__'):
  main() import sys sys def main():
  input = sys.stdin.readline
  n, k = map(int , input().split())
  p_list = list(map(int, input().split()))
  c_list = list(map(int, input().split()))
  res = -float('inf')
  
  for s in range(n):
    S = []
    i = p_list[s] - 1
    S.append(c_list[i])
    while i != s:
      i = p_list[i]-1
      S.append(S[-1] + c_list[i])
    if k <= len(S):
      score = max(S[:k])
    elif S[-1] <= 0:
      score = max(S)
    else:
      score1 = S[-1] * (k//len(S) - 1)
      score1 += max(S)
      
      score2 = S[-1] * (k//len(S))
      r = k%len(S)
      if r!=0:
        score2 += max(0, max(S[:r]))
      score = max(score1, score2)
    res = max(res, score)
  print(res)
       main input = sys.stdin.readline input sys.stdin.readline sys.stdin sys stdin readline n, k = map(int , input().split()) n map(int , input().split()) map int input().split() ().split () input split k p_list = list(map(int, input().split())) p_list list(map(int, input().split())) list map(int, input().split()) map int input().split() ().split () input split c_list = list(map(int, input().split())) c_list list(map(int, input().split())) list map(int, input().split()) map int input().split() ().split () input split res = -float('inf') res -float('inf') float('inf') float 'inf' for s in range(n):
    S = []
    i = p_list[s] - 1
    S.append(c_list[i])
    while i != s:
      i = p_list[i]-1
      S.append(S[-1] + c_list[i])
    if k <= len(S):
      score = max(S[:k])
    elif S[-1] <= 0:
      score = max(S)
    else:
      score1 = S[-1] * (k//len(S) - 1)
      score1 += max(S)
      
      score2 = S[-1] * (k//len(S))
      r = k%len(S)
      if r!=0:
        score2 += max(0, max(S[:r]))
      score = max(score1, score2)
    res = max(res, score)
   s range(n) range n S = [] S [] i = p_list[s] - 1 i p_list[s] - 1 p_list[s] p_list s 1 S.append(c_list[i]) S.append S append c_list[i] c_list i while i != s:
      i = p_list[i]-1
      S.append(S[-1] + c_list[i])
     i != s i s i = p_list[i]-1 i p_list[i]-1 p_list[i] p_list i 1 S.append(S[-1] + c_list[i]) S.append S append S[-1] + c_list[i] S[-1] S -1 c_list[i] c_list i if k <= len(S):
      score = max(S[:k])
    elif S[-1] <= 0:
      score = max(S)
    else:
      score1 = S[-1] * (k//len(S) - 1)
      score1 += max(S)
      
      score2 = S[-1] * (k//len(S))
      r = k%len(S)
      if r!=0:
        score2 += max(0, max(S[:r]))
      score = max(score1, score2)
     k <= len(S) k len(S) len S score = max(S[:k]) score max(S[:k]) max S[:k] S :k k elif S[-1] <= 0:
      score = max(S)
     S[-1] <= 0 S[-1] S -1 0 score = max(S) score max(S) max S score1 = S[-1] * (k//len(S) - 1) score1 S[-1] * (k//len(S) - 1) S[-1] S -1 k//len(S) - 1 k//len(S) k len(S) len S 1 score1 += max(S) score1 max(S) max S score2 = S[-1] * (k//len(S)) score2 S[-1] * (k//len(S)) S[-1] S -1 k//len(S) k len(S) len S r = k%len(S) r k%len(S) k len(S) len S if r!=0:
        score2 += max(0, max(S[:r]))
       r!=0 r 0 score2 += max(0, max(S[:r])) score2 max(0, max(S[:r])) max 0 max(S[:r]) max S[:r] S :r r score = max(score1, score2) score max(score1, score2) max score1 score2 res = max(res, score) res max(res, score) max res score print(res) print res if (__name__=='__main__'):
  main() __name__=='__main__' __name__ '__main__' main() main def main():
  input = sys.stdin.readline
  n, k = map(int , input().split())
  p_list = list(map(int, input().split()))
  c_list = list(map(int, input().split()))
  res = -float('inf')
  
  for s in range(n):
    S = []
    i = p_list[s] - 1
    S.append(c_list[i])
    while i != s:
      i = p_list[i]-1
      S.append(S[-1] + c_list[i])
    if k <= len(S):
      score = max(S[:k])
    elif S[-1] <= 0:
      score = max(S)
    else:
      score1 = S[-1] * (k//len(S) - 1)
      score1 += max(S)
      
      score2 = S[-1] * (k//len(S))
      r = k%len(S)
      if r!=0:
        score2 += max(0, max(S[:r]))
      score = max(score1, score2)
    res = max(res, score)
  print(res)
       def main():
  input = sys.stdin.readline
  n, k = map(int , input().split())
  p_list = list(map(int, input().split()))
  c_list = list(map(int, input().split()))
  res = -float('inf')
  
  for s in range(n):
    S = []
    i = p_list[s] - 1
    S.append(c_list[i])
    while i != s:
      i = p_list[i]-1
      S.append(S[-1] + c_list[i])
    if k <= len(S):
      score = max(S[:k])
    elif S[-1] <= 0:
      score = max(S)
    else:
      score1 = S[-1] * (k//len(S) - 1)
      score1 += max(S)
      
      score2 = S[-1] * (k//len(S))
      r = k%len(S)
      if r!=0:
        score2 += max(0, max(S[:r]))
      score = max(score1, score2)
    res = max(res, score)
  print(res)
       main
import sys
def main():
  input = sys.stdin.readline
  n, k = map(int , input().split())
  p_list = list(map(int, input().split()))
  c_list = list(map(int, input().split()))
  res = -float('inf')
  
  for s in range(n):
    S = []
    i = p_list[s] - 1
    S.append(c_list[i])
    while i != s:
      i = p_list[i]-1
      S.append(S[-1] + c_list[i])
    if k <= len(S):
      score = max(S[:k])
    elif S[-1] <= 0:
      score = max(S)
    else:
      score1 = S[-1] * (k//len(S) - 1)
      score1 += max(S)
      
      score2 = S[-1] * (k//len(S))
      r = k%len(S)
      if r!=0:
        score2 += max(0, max(S[:r]))
      score = max(score1, score2)
    res = max(res, score)
  print(res)
      

if (__name__=='__main__'):
  main()